Fisher information of accelerated two-qubit systems

2018 ◽  
Vol 32 (05) ◽  
pp. 1850050 ◽  
Author(s):  
N. Metwally
Keyword(s):  
Analytical Solution ◽  
Fisher Information ◽  
General State ◽  
Initial State ◽  
Werner State ◽  
Pure States ◽  
X State ◽  
Different Parts ◽  
Degree Of Entanglement

In this paper, Fisher information for an accelerated system initially prepared in the X-state is discussed. An analytical solution, which consists of three parts: classical, the average over all pure states and a mixture of pure states, is derived for the general state and for Werner state. It is shown that the Unruh acceleration has a depleting effect on the Fisher information. This depletion depends on the degree of entanglement of the initial state settings. For the X-state, for some intervals of Unruh acceleration, the Fisher information remains constant, irrespective to the Unruh acceleration. In general, the possibility of estimating the state’s parameters decreases as the acceleration increases. However, the precision of estimation can be maximized for certain values of the Unruh acceleration. We also investigate the contribution of the different parts of the Fisher information on the dynamics of the total Fisher information.

Color Entanglement in Hadronic Processes for Transverse Momentum Dependent Parton Distribution Functions

2015 ◽  
Vol 37 ◽  
pp. 1560022
Author(s):  
M. G. A. Buffing ◽  
P. J. Mulders
Keyword(s):  
Transverse Momentum ◽  
Parton Distribution ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Initial State ◽  
Color Flow ◽  
Transverse Momentum Dependent ◽  
Gauge Link ◽  
Azimuthal Asymmetries ◽  
Different Parts

In the description of protons, we go beyond the ordinary collinear parton distribution functions (PDFs), by including transverse momentum dependent PDFs (TMDs). As such, we become sensitive to polarization modes of the partons and protons that one cannot probe without accounting for transverse momenta of partons, in particular when looking at azimuthal asymmetries. Hadronic processes require the inclusion of gluon contributions forming the gauge links, which are path-ordered exponentials tracing the color flow. In processes with two hadrons in the initial state, such as Drell-Yan (DY), the gauge links from different parts of the process get entangled. We show that in color disentangling this gauge link structure, one becomes sensitive to this color flow. After disentanglement, particular combinations of TMDs will require a different numerical color factor than one naively might have expected. Such color factors will even play a role for azimuthal asymmetries in the simplest hadronic processes such as DY.

scholarly journals XVI. An abridged state of the weather at London in the year 1774, collected from the Meteorological journal of the Royal Society

1775 ◽  
Vol 65 ◽  
pp. 167-193
Keyword(s):  
General Result ◽  
Royal Society ◽  
General State ◽  
History Of ◽  
Distinct Branch ◽  
Experimental History ◽  
Different Parts

Although the practice of keeping meteorological journals is, of late years, become very general, no information of any importance hath yet been derived from it. The reason of which perhaps may be, that after great pains and attention bestowed in registering particulars, as they occur, with a scrupulous minuteness, observers have not taken the trouble to form, at proper intervals of time, compendious abstracts of their records, exhibiting the general result of their observations in each distinct branch of meteorology, The following tables are given as an example of the method that may be taken in future to remedy this neglect. With the general state of the barometer and thermometer, already given at the end of the meteorological journal, they form a history of the weather at London during the last year. If the example were to be followed, in different parts of the kingdom, we might in time be furnished with an experimental history of the weather of our island.

scholarly journals Drained cavity expansion analysis with a unified state parameter model for clay and sand

2018 ◽  
Vol 55 (7) ◽  
pp. 1029-1040 ◽  
Author(s):  
Pin-Qiang Mo ◽  
Hai-Sui Yu
Keyword(s):  
Analytical Solution ◽  
Plastic Region ◽  
State Parameter ◽  
Auxiliary Variable ◽  
Cavity Expansion ◽  
Large Strains ◽  
Initial State ◽  
Model Soil ◽  
Spacing Ratio ◽  
Soil Behaviour

This paper presents an analytical solution for drained expansion in both spherical and cylindrical cavities with a unified state parameter model for clay and sand (CASM). The solution developed here provides the stress and strain fields during the expansion of a cavity from an initial to an arbitrary final radius. Small strains are assumed for the elastic region and large strains are applied to soil in the plastic region by using logarithmic strain definitions. Since its development, the unified CASM model has been demonstrated by many researchers to be able to capture the overall soil behaviour for both clay and sand under both drained and undrained loading conditions. In this study, the CASM model is used to model soil behaviour whilst a drained cavity expansion solution is developed with the aid of an auxiliary variable. This is an extension of the undrained solution presented by the authors in 2017. The parametric study investigates the effects of various model constants including the stress-state coefficient and the spacing ratio on soil stress paths and cavity expansion curves. Both London clay and Ticino sand are modelled under various initial stress conditions and initial state parameters. The newly developed analytical solution highlights the potential applications in geotechnical practice (e.g., for the interpretation of cone penetration test data) and also provides useful benchmarks for numerical simulations of cavity expansion problems in critical state soils.

scholarly journals Bidirectional teleportation using Fisher information

2020 ◽  
Vol 35 (33) ◽  
pp. 2050272
Author(s):  
C. Seida ◽  
A. El Allati ◽  
N. Metwally ◽  
Y. Hassouni
Keyword(s):  
Fisher Information ◽  
Uncertainty Principle ◽  
Quantum Fisher Information ◽  
Single Parameter ◽  
Numerical Calculations ◽  
Initial State ◽  
Better Than

In this contribution, we reformulated the bidirectional teleportation protocol suggested in Ref. 7, by means of Bloch vectors as well as the local operations are represented by using Pauli operators. Analytical and numerical calculations for the teleported state and Fisher information are introduced. It is shown that both quantities depend on the initial state settings of the teleported qubits and their triggers. The Fidelities and the Fisher information of the bidirectionally teleported states are maximized when the qubit and its trigger are polarized in the same direction. The minimum values are predicted if both initial qubits have different polarization or nonzero phase. The maximum values of the Fidelity and the quantum Fisher information are the same, but they are predicted at different polarization angles. We display that the multi-parameter form is much better than the single parameter form, where it satisfies the bounds of classical, entangled systems and the uncertainty principle.

Quantum feedback control for qubit-qutrit entanglement

2016 ◽  
Vol 16 (7&8) ◽  
pp. 597-614
Author(s):  
Tiantian Ma ◽  
Jun Jing ◽  
Yi Guo ◽  
Ting Yu
Keyword(s):  
Feedback Control ◽  
Open System ◽  
Control Mechanism ◽  
Initial State ◽  
Level Atom ◽  
Control Scheme ◽  
Quantum Feedback ◽  
Local Feedback ◽  
Quantum Open System ◽  
Different Parts

We study a hybrid quantum open system consisting of two interacting subsystems formed by one two-level atom (qubit) and one three-level atom (qutrit). The quantum open system is coupled to an external environment (cavity) via the qubit-cavity interaction. It is found that the feedback control on different parts of the system (qubit or qutrit) gives dramatically different asymptotical behaviors of the open system dynamics. We show that the local feedback control mechanism acting on the qutrit subsystem is superior than that on the qubit in the sense of improving the entanglement. Particularly, the qutrit-control scheme may result in an entangled steady state, depending on the initial state.

scholarly journals Time-dependent interaction between a two-level atom and a su(1,1) Lie algebra quantum system

2017 ◽  
Vol 31 (15) ◽  
pp. 1750211 ◽  
Author(s):  
M. Sebaweh Abdalla ◽  
E. M. Khalil ◽  
A.-S. F. Obada
Keyword(s):  
Coupling Parameter ◽  
Functional Dependence ◽  
Integrability Condition ◽  
Initial State ◽  
Atomic Inversion ◽  
Mode Field ◽  
Level Atom ◽  
Degree Of Entanglement ◽  
Algebraic Operators ◽  
Dependent Interaction

The problem of the interaction between a two-level atom and a two-mode field in the parametric amplifier-type is considered. A similar problem appears in an ion trapped in a two-dimensional trap. The problem is transformed into an interaction governed by su(1,1) Lie algebraic operators with phase and coupling parameter depending on time. Under an integrability condition, that relates phase and coupling, a solution to the wavefunction is obtained using the Schrödinger equation. The effects of the functional dependence of the coupling and the initial state of the two-level atom on atomic inversion, the degree of entanglement, the fidelity and the Glauber second-order correlation function are investigated. It is shown that the acceleration term plays an important role in controlling the function behavior of the considered quantities.

scholarly journals Quantum Fisher Information in Two-Qubit Pure States

2010 ◽  
Vol 49 (10) ◽  
pp. 2463-2475 ◽  
Author(s):  
Wan-Fang Liu ◽  
Li-Hua Zhang ◽  
Chun-Jie Li
Keyword(s):  
Fisher Information ◽  
Quantum Fisher Information ◽  
Pure States

Fisher Information and Quantum Squeezing Properties of Gaussian Pure States

2012 ◽  
Vol 571 ◽  
pp. 283-286
Author(s):  
Jia Qiang Zhao ◽  
Lian Zhen Cao ◽  
Huai Xin Lu
Keyword(s):  
Fisher Information ◽  
Quantum States ◽  
Pure States ◽  
Definition Of ◽  
Fisher Length

In this paper the Fisher information of Gaussian pure States is studied. Based on the definition of joint non-classical properties, we calculate the non-classical properties of Gaussian pure States. The results show that the Fisher information and Fisher length are efficacious tools to study the non-classical properties of quantum States.

scholarly journals Subsystem complexity after a local quantum quench

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Giuseppe Di Giulio ◽  
Erik Tonni
Keyword(s):  
Fisher Information ◽  
Temporal Evolution ◽  
Entanglement Entropy ◽  
Circuit Complexity ◽  
Information Geometry ◽  
Covariance Matrices ◽  
Qualitative Behaviour ◽  
Initial State ◽  
Local Quantum ◽  
Logarithmic Growth

Abstract We study the temporal evolution of the circuit complexity after the local quench where two harmonic chains are suddenly joined, choosing the initial state as the reference state. We discuss numerical results for the complexity for the entire chain and the subsystem complexity for a block of consecutive sites, obtained by exploiting the Fisher information geometry of the covariance matrices. The qualitative behaviour of the temporal evolutions of the subsystem complexity depends on whether the joining point is inside the subsystem. The revivals and a logarithmic growth observed during these temporal evolutions are discussed. When the joining point is outside the subsystem, the temporal evolutions of the subsystem complexity and of the corresponding entanglement entropy are qualitatively similar.

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